Descriptions and actions are really important in an RP. they break up text, but can also really setthe seen, and even more importantly, if done well they can bring a reader into the RP and really help them visualize what is happening.

That being said, there is a correct way to do descriptions.

Example:The Hitman walks into a room and sits on a bench

Lets make that better...

The Hitman steps into a well lit room, and for a few moments quietly gazes around the room, before heading towards an old wooden bench and taking a seat.

See how the second one is better?

The Hitman slowly paces into a room with several bright lights hanging overhead. For a few moments The Hitman silently gazes around the room, before heading towards an rickety old wooden bench. The Hitman finally arrives at the bench, looks it over, and sets himself down on it.

That is even better, it really sets the mood of the scene, as well as giving the reader a good visual.(Be wary, if you go into ridiculous detail, like in some novels, it is really annoying to read as a reader, so be detailed, but not too detailed)

But you can't have actions that descriptive throughout the RP, because actions primary goal is to break up text, when the action is four lines long, it breaks up the text too much, interrupting the flow of the RP.

So a nice detailed action at the beginning of a scenario is very nice, and sets the mood.

But in the middle, keep them shorter. Lets say in my RP someone else came in the room, and we talked, then I get up.

Its okay to say

The Hitman gets up from the bench and approaches Crashoverride

Not very descriptive, but it doesn't interrupt the flow of the text.

TheHitman gets up from the rickety old bench, which quakes as he stands. He then fixes his pants, and slowly steps towards Crashoverride, with an angry look on his face

That action is a little bit too much, maybe not if its done once or twice, but if you do a long RP, and have 6-8 actions in it, and they're all that long, it gets annoying. Also, I had already described the bench in that scene, but I did it again in that action, that is redundant, that's like if in every action in that RP I stated that the lights were bright, its old info that slows the flow.

So in summary having good descriptions and actions in an RP are very important, and can really set a scene, and bring the reader into it, and a longer description is fine, as long as it isn't used constantly, just try to cut back, maybe only use it for the entrance and exit, or a part where you want a dramatic build up, but using it throughout it is repetitive, and interrupts the flow of an RP, defeating the purpose of actions in the first place.